/System/Library/Frameworks/Ruby.

MacOS 升级后pod 会出现此问题，解决办法：重新安装 pod 即可

1、更新gem：sudo gem update --system， 如果失败执行sudo gem install -n /usr/local/bin cocoapods

2、删除gem源：gem sources --remove https://ruby.taobao.org/

3、修改gem源：gem sources -a https://gems.ruby-china.org

4、查看gem源是否是最新的：gem sources -l

5、升级cocoapods：sudo gem install -n /usr/local/bin cocoapods --pre

6、查看升级后的cocoapods版本：pod --version